A recent clinical study demonstrated a possible connection between coffee consumption and heart health. The researchers performed a 6-week trial with 191 individuals, all of whom were heavy coffee drinkers (average of 5 cups/day) prior to the experiment, but none of whom were smokers. They divided the 191 participants into three groups: no coffee consumption, 1-3 cups/day, and 4 or more cups/day. They measured blood levels of cholesterol and homocysteine as indicators of heart health. Only the no-coffee group showed a significant drop in both indicators. Previous studies had demonstrated that decreases of the magnitude observed in the no-coffee group could cut the incidence of heart disease by 10-15%.

a) What is the problem/question being studied?

b) What is the hypothesis?

c) What is the experimental variable?

d) List the controls.

e) What is being measured to test the hypothesis?

a) The problem being studies is whether coffee consumption has any effect on heart health or not.

A scientific research always begins with an observation followed by a question which needs to be answered by the scientific method of research. In the following scenario, the problem that was observed was whether coffee consumption affected the health of the heart or not.

b) The hypothesis can be 'If the consumption of coffee is stopped, then hear health can be maintained.'

In the scientific method of research, a hypothesis can be described as a tentative statement which can either be proved as right or wrong. If a hypothesis comes out to be wrong, then another hypothesis can be generated.

c) The experimental variable is the amount of coffee being given to the 191 participants.

The experimental variable is the variable which is under study in a scientific experiment. It might contain of a dependent and independent variable.

d) Controls is that the all heave drinkers of coffee were chosen for the experiment. All were non - smokers.

A control group can be described as a group in the scientific experiment in which no changes are made. The results of the changes which occurred in the experimental group are compared with the control group.

e) The blood levels of cholesterol and homocysteine are being measured to test the hypothesis.

In the scientific method of research, a hypothesis is tested through experiments. The results of these experiments conclude whether the hypothesis is true of false. Based on the experiment, results are generated and conclusions are drawn.